Hierarchical, deterministic, one-time login tokens

ABSTRACT

Methods, systems and articles of manufacture for hierarchical, deterministic, one-time login tokens are provided herein. A method includes generating a plurality of items of key information comprising a first item of key information and a second item of key information that is derived from the first item of key information; attributing a distinct authorization level to the plurality of items of key information to create a modified version of the first item of key information and a modified version of the second item of key information; providing the modified version of the first item of key information to a first cryptographic device to be used in an authentication request associated with a second cryptographic device; and providing the modified version of the second item of key information to the second cryptographic device to be used in an authentication request with the first cryptographic device.

FIELD

The field relates generally to cryptography, and more particularly touser authentication techniques.

BACKGROUND

In order to gain access to applications, systems, and/or other resourcesvia a computer or another user device, users are often required toauthenticate themselves by entering authentication information. Suchauthentication information may include, for example, passwords, secrets,and/or security tokens. Such authentication information may include, forexample, one-time passwords or login tokens.

Challenges facing existing token-based user authentication techniques,however, can include attacks by an adversary that compromises and/orimpersonates a user by stealing the user's credentials. In otherattacks, an adversary can control the operation of an authenticationserver over an extended period of time, wherein such an adversary cansubvert the authentication process, impersonating a user even if theuser's credentials are periodically refreshed.

SUMMARY

One or more illustrative embodiments of the present invention providehierarchical, deterministic, one-time login tokens and techniques foruse thereof.

In accordance with one embodiment of the invention, a first method isprovided comprising the steps of: generating a plurality of items of keyinformation comprising (i) a first item of key information and (ii) asecond item of key information that is derived from the first item ofkey information; attributing a distinct authorization level, from a setof multiple authorization levels, to the plurality of items of keyinformation to create (i) a modified version of the first item of keyinformation and (ii) a modified version of the second item of keyinformation; providing the modified version of the first item of keyinformation to a first cryptographic device to be used in connectionwith processing an authentication request associated with a secondcryptographic device; and providing the modified version of the seconditem of key information to the second cryptographic device to be used inconnection with a submission of an authentication request to the firstcryptographic device.

In accordance with another embodiment of the invention, a second methodis provided comprising the steps of: processing an indication, generatedby a user, to access a protected resource on a cryptographic device;generating, in response to said processing, a request to authenticatethe user to the cryptographic device to access the protected resource,wherein said generating comprises encrypting a message using an item ofkey information, wherein the item of key information includes adesignation of a distinct authorization level attributed to the userfrom a set of multiple authorization levels, and wherein the messagecomprises: an incremental item of cryptographic information to be usedexclusively in connection with the request to authenticate the user tothe cryptographic device to access the protected resource; andinitiating a transmission of the request to the cryptographic device.

In accordance with yet another embodiment of the invention, a thirdmethod is provided comprising the steps of: processing a request toauthenticate a user to access a protected resource, wherein the requestcomprises an encrypted message including an item of cryptographicinformation, and wherein said processing comprises: decrypting theencrypted message using an item of key information, wherein the item ofkey information includes a designation of a distinct authorizationlevel, selected from a set of multiple authorization levels; andcomparing the item of cryptographic information to one or more items ofcryptographic information observed in connection with one or moreprevious authentication requests to determine a status of the item ofcryptographic information in relation to the one or more items ofcryptographic information observed in connection with the one or moreprevious authentication requests; and resolving the authenticationrequest based on (i) said decrypting and (ii) said comparing.

In accordance with another embodiment of the invention, a cryptographicdevice is provided that includes a processor coupled to a memory andconfigured to implement noted method steps detailed herein.

The methods and cryptographic devices of the illustrative embodimentsovercome one or more of the problems associated with the conventionaltechniques described previously, and provide the ability for multiplethird party systems to authenticate between themselves without requiringintegration among the third party systems. These and other features andadvantages of the present invention will become more readily apparentfrom the accompanying drawings and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example network environment in whichone or more embodiments of the present invention can operate;

FIG. 2 is a diagram illustrating an example embodiment of the invention;

FIG. 3 is a diagram illustrating an authentication exchange mechanism,according to an example embodiment of the invention;

FIG. 4 is a flow diagram illustrating techniques according to an exampleembodiment of the invention;

FIG. 5 is a flow diagram illustrating techniques according to an exampleembodiment of the invention;

FIG. 6 is a flow diagram illustrating techniques according to an exampleembodiment of the invention;

FIG. 7 is a diagram illustrating an example embodiment of communicationsystems that may incorporate functionality according to one or moreembodiments of the invention; and

FIG. 8 is a system diagram of an exemplary cryptographic device on whichat least one embodiment of the invention can be implemented.

DETAILED DESCRIPTION

As will be described, one or more embodiments of the invention includesthe generation and utilization of hierarchical, deterministic, one-timelogin tokens to enable users of a first system to have efficient accessto particular data on a second system. Such generation and utilizationof one-time login tokens, according to one or more embodiments of theinvention, requires no extra or additional configuration to associatedweb servers, and further requires no extra or additional accounts to becreated for the user on either the first system or the second system.Additionally, at least one embodiment of the invention includesincorporating an ability to set and/or specify authorization levels.

Illustrative embodiments of the present invention will be describedherein with reference to exemplary cryptographic devices. It is to beappreciated, however, that one or more embodiments of the invention arenot restricted to use with the particular illustrative system and deviceconfigurations shown.

Accordingly, the term “cryptographic device,” as used herein, isintended to be construed broadly so as to encompass any type ofprocessing device that incorporates cryptographic functionality (such asa computer, server, mobile telephone, radio-frequency identification(RFID) tag or reader, authentication token, etc.). Similarly, the term“authentication server” should be understood to encompass any type ofprocessing device or set of such devices that is operative toauthenticate information provided by an authentication token generatoror other type of device. As used herein, an “authentication server” neednot be a network-based server, and may be implemented as a portion of adevice that performs other functions, as a combination of multipleservers or other devices, or in other forms.

Additionally, the term “authentication information,” as used herein, isintended to include passwords, passcodes, security tokens, answers tolife questions, or other authentication credentials, or values derivedfrom such authentication credentials, or more generally any otherinformation that a user may be required to submit in order to obtainaccess to an access-controlled application or resource.

Also, the term “cryptographic information,” as used herein, is intendedto include any number, value, key, or other information utilized infurtherance of a cryptographic function or process.

FIG. 1 illustrates an example cryptographic device 110-1 communicatingwith another example cryptographic device 110-N in an attempt to accessa protected resource 170 (on cryptographic device 110-N) over a network160. In an example implementation, a user must authenticate with one ora plurality of authentication servers 150-1 through 150-N (hereinafter,collectively referred to as authentication servers 150) usingauthentication information (such as a security token) generated by asecurity token generator 130 (hereinafter, referred to as security token130) before obtaining access to the protected resource 170.Additionally, while shown in the FIG. 1 example as being resident oncryptographic device 110-N, in one or more embodiments of the invention,the protected resource 170 can include, for example, a separatecryptographic device, a component of a system, particular data on asystem associated with cryptographic device 110-1, and/or particulardata on a system not associated with cryptographic device 110-1 (such ascryptographic device 110-N, as shown in the example FIG. 1).

Referring back to FIG. 1, the network 160 can include, for example, aglobal computer network such as the Internet, a wide area network (WAN),a local area network (LAN), a satellite network, a telephone or cablenetwork, or various portions or combinations of these and other types ofnetworks.

According to one example embodiment of the invention, the user of thecryptographic device 110-1 is authenticated, using authenticationinformation such as a one-time login token generated by the securitytoken generator 130, by authentication servers 150. The exemplarycommunications among the system elements 110-1, 130, 150 and 110-N ofFIG. 1 to achieve joint authentication by the authentication servers 150is discussed further below.

It is to be appreciated that a given embodiment of the disclosed systemmay include multiple instances of cryptographic device 110-1 and/or110-N, security token 130 and protected resource 170, and possibly othersystem components, although the noted instances of such components areshown in the simplified system diagram of FIG. 1 for clarity ofillustration.

The security token 130 is shown in FIG. 1 as being resident oncryptographic device 110-1. However, in one or more embodiments of theinvention the security token 130 may be separate from and electricallyconnected to the cryptographic device 110-1. The security token 130 maybe implemented, for example, using the RSA SecurID® user authenticationtoken commercially available from RSA Security Inc. of Bedford, Mass.,U.S.A. The security token 130 may be a server or other type of modulethat is accessible over the network 160, or it may be a softwarecomponent resident on the cryptographic device 110-1. As anotheralternative, security token 130 may be distributed over multipledevices, one of which may be the cryptographic device 110-1. By way ofyet another alternative, security token 130 may be resident on and/orconnected to the authentication server 150. In such an embodiment of theinvention, the security token 130 can be on an authentication server 150and, as part of a client request to the authentication server 150(server N, in this example), the security token 130 can respond backwith a command such as, for example, “Get resource X from server N+1using Token Y.”

Accordingly, it should be appreciated that one or more additionalimplementations are within the scope of embodiments of the invention, aswould be apparent to a person of ordinary skill in the art.

Cryptographic devices 110-1 and 110-N, as depicted in FIG. 1 (and alsoadditionally described in connection with the example device illustratedin FIG. 8), include a processor 112-1 and 112-N, respectively, coupledto a memory 114-1 and 114-N, respectively, as well as a networkinterface 116-1 and 116-N, respectively. As further detailed herein,each such processor (112) is coupled to a memory (114) and configured toimplement noted actions internally and/or over network 160 (via anetwork interface (116)) in connection with other devices such as, forexample, authentication servers 150 and one or more other cryptographicdevices. Cryptographic devices 110-1 and 110-N may, respectively,represent a portable device, such as a mobile telephone, personaldigital assistant (PDA), wireless email device, game console, etc.Cryptographic devices 110-1 and 110-N may, respectively, alternativelyrepresent a desktop or laptop personal computer (PC), a microcomputer, aworkstation, a mainframe computer, a wired telephone, a television settop box, or any other cryptographic device which can benefit from theuse of authentication techniques in accordance with one or moreembodiments of the invention.

Cryptographic devices 110-1 and 110-N may also be referred to herein assimply a “user.” The term “user,” as used in this context, should beunderstood to encompass, by way of example and without limitation, auser device, a person utilizing or otherwise associated with the device,or a combination of both. An operation described herein as beingperformed by a user may therefore, for example, be performed by a userdevice, a person utilizing or otherwise associated with the device, orby a combination of both the person and the device. Similarly, apassword, login token, or other authentication information described asbeing associated with a user may, for example, be associated with acryptographic device (such as 110-1 and/or 110-N), a person utilizing orotherwise associated with the device, or a combination of both theperson and the device.

As also depicted in FIG. 1, the authentication servers 150 are typicallyassociated with a third party entity, such as an authenticationauthority, that processes authentication requests on behalf of webservers and other resources, as well as verifies the authenticationinformation that is presented by a cryptographic device (such as 110-1,for example). Alternatively, in one or more embodiments of theinvention, the authentication server 150 can be resident on and/or partof one of the parties and/or entities seeking authentication. Forexample, in such an implementation, the authentication server 150 couldbe embedded inside a component such as, for instance, a web browser.

Further, the protected resource 170 may be, for example, anaccess-controlled application, a remote application server such as a website or other software program or hardware device that is accessed bythe cryptographic device 110 over a network 160. Additionally, as notedabove, the protected resource 170 can also be, for example, a separatecryptographic device, a component of a system or separate cryptographicdevice (such as illustrated in the FIG. 1 example), particular data on asystem associated with cryptographic device 110-1, and/or particulardata on a system not associated with cryptographic device 110-1 (such ascryptographic device 110-N, as depicted in the FIG. 1 example). In otherwords, a protected resource 170 is a resource that grants user accessresponsive to an authentication process, as will be described in greaterdetail below.

Accordingly, as discussed above, in order to authenticate a user (suchas depicted by cryptographic device 110-1, for example) to a system(such as depicted by cryptographic device 110-N containing protectedresource 170, for example), a security token or secret (such as apassword or a certificate) can be used. Generally, if the userconnecting to a system knows this secret, then the user is grantedaccess to the system.

As such, at least one embodiment of the invention includes the aspect ofgenerating (via security token generator 130, for example) and sharing asecret between two systems, so that if System A redirects a user(cryptographic device 110-1, for example) to System B (cryptographicdevice 110-N, for example), System A would include the secret in therequest (to redirect the user to System B). When such a request isreceived by System B, System B would verify the presence of the secretin the request, and if valid, authorize the user. In such an embodimentof the invention, the authentication servers 150 would be resident onSystem B, and/or offloaded by System B to a third party system to carryout the authentication process.

Such an authentication mechanism, however, may allow the possibility fora third party to eavesdrop on the communication (including theredirected user) and subsequently re-use the secret to gain unwantedaccess to System B. Consequently, at least one embodiment of theinvention can also include incorporating an aspect of public/privatecryptography to hide the secret while proving ownership of the secret.In such an embodiment, System B is given a private key (Priv1) andSystem A is given a public key (Pub1) based on Priv1. In at least oneembodiment of the invention, the system and/or user that controls theauthentication process generates the keys. In one or more otherembodiments of the invention, a third party system can generate thekeys. In such an embodiment, the third party system can generate amaster key, and then generate sub-keys off the master key for anysystems desired to be protected (such as, for example, System B). Byusing such an implementation, the user and/or system would only need tomaintain a copy of the master key as a backup, and generate any sub-keysas necessary on demand.

Further, System A can use Pub1 to generate a token (as part of anauthentication request submitted to System B) that proves that System Ahas the public key. For example, System A can encrypt a message withPub1 so that only System B can decrypt the message because System Bholds Priv1 (and Priv1 is required to decrypt the message), therebyproving to System B that System A holds Pub1.

Additionally, in such an embodiment of the invention, when forwarding orredirected a user to System B, System A can include this proof that it(System A) has the public key in its possession that corresponds to theSystem B private key. When System B receives an authentication request,System B will attempt to use its private key to unencrypt thecorresponding message (encrypted with System A's public key), and ifSystem B is successful in doing so, System B will authenticate the user.

While this approach does prevent an eavesdropper from obtaining accessto the secret, such an authentication mechanism may, however, allow thepossibility for a third party to eavesdrop on the communication andsubsequently use the same encrypted value on a future request to accessthe same information at a later time. If an eavesdropper (or a malicioususer) is able to observe or obtain one such authentication request, thateavesdropper could potentially re-use this same authentication requestat a later time to gain access to the system.

Consequently, at least one embodiment of the invention can also includeincorporating an incrementing nonce to prevent replay attacks. As usedherein, a nonce refers to a number or other form of cryptographicinformation that can be embedded in a cryptographic communication, suchas embedded in an encrypted message (or be the only thing encrypted),that increments with each subsequent cryptographic communication (forexample, increments by one each time an authentication request is made).

By way of illustration, consider the following implementation of such anembodiment of the invention. System A starts with the nonce at a valueof 0, and each time that System A makes an authentication request,System A increases the nonce by 1, encrypts the nonce in a message usinga public key (that is based on a private key of System B), and includesthe nonce in the authentication request to the server (or to System B).

System B keeps track of the highest nonce value that it (System B) hasreceived in an authentication request to that point. Every time System Breceives a new authentication message or request, System Bunencrypts/decrypts the nonce using its private key and compares thevalue of the nonce against the previously highest nonce value. If thedecrypted nonce value is greater than the previously highest receivednonce value, then System B authenticates the user and saves the newnonce value as the highest value. If the unencrypted nonce value isequal to or lower than a previously received nonce value, then System Bcan assume that a replay attack is under way and deny the authenticationrequest.

By way of further example, in one or more embodiments of the invention,the current time (in milliseconds, for instance) can be used as thenonce value.

Additionally, at least one embodiment of the invention includesincorporating an ability to communicate multiple/different authorizationlevels in conjunction with using pre-defined public and private keys. Byway of example, in certain contexts, enterprise settings, and/or productconfigurations, different users may be associated with different roles,and those different roles may be associated with different levels ofauthorization. Consider, for example, a vulnerability risk managementsystem that designates the following user roles: administrator (Admin),operations (Ops), and read-only.

FIG. 2 is a diagram illustrating an example embodiment of the invention.In the FIG. 2 example, the role of Admin is the highest level; that is,the role of Admin is associated with more permissions/authorizationsthan the role of Ops, which is, in turn, associated with morepermissions/authorizations than the role of read-only. These roles forma hierarchy wherein different permissions (that is, authorizations) aregranted for each role. Further, the roles above a given role (in thehierarchy) contain all of permissions below the given role plus one ormore additional permissions.

Also, in FIG. 2 (and elsewhere herein), “m” refers to the master node(or “seed”). From the master node, N private/public key pairs can begenerated. “m/0” and “m/1” refer to a generated sub-key of index 0 andindex 1, respectively, off the seed 201. From any private/public key,additional sub-keys can be derived. Accordingly, in FIG. 2, “m/0/0” and“m/1/0” refer to the key at index 0 derived from the key “m/0,” and thekey at index 0 derived from the key “m/1,” respectively. Additionally, aprivate key can generate private/public sub-keys, whereas a public keycan only generate public sub-keys (that would match the public keygenerated from a private key with the same derivation path).

Referring specifically to the example depicted in FIG. 2, a single seed(m) 201 can be used to generate multiple child keys to authenticate Nnumber of third party systems (FIG. 2 illustrates two such systems:System B and System C). Additionally, System A can send any sub-level ofauthorization to any third party system. In the example depicted in FIG.2, System A allows permissions associated with Admin (m/0) 202, Ops(m/0/0) 204, and Ready-Only (m/0/0/0) 206 to System B, but System Aallows only permissions associated with Ops (m/1/0) 210 and Read-Only(m/1/0/0) 212 to System C. As illustrated in this example, System A doesnot allow permissions associated with Admin (m/1) 208 to System C.

Further, in one or more embodiments of the invention, System A canrevoke permissions from System B and/or System C, for example, byinternally marking any child keys from m/0 (202) or m/1 (208) as nolonger valid.

Also, in one or more embodiments of the invention, additional systems orsub-systems can be authenticated in a hierarchical fashion if allowed bySystem A. By way of example, System A can allow System B to sharederived keys (for instance, another Read-Only-level key (m/0/0/1)) withone or more other systems (for example, System D) without System Ahaving to specifically share keys with System D, because, in such anembodiment, System B can derive public child keys from any existingpublic key (for instance, System B can derive m/0/0/1 from m/0/0). Suchan embodiment can include enabling specific management by System A todetermine which branches of the tree are to be allowed (if any).

Accordingly, to allow different roles to be mapped to differentpublic/private key pairs, at least one embodiment of the inventionincludes deriving a key tree from a single seed value. In such anembodiment, a random seed is first generated, then a public and privateextended key pair is generated based thereon. To generate the master keyor seed “m” from a randomly generated value (for example, a random 256buffer), the random value can be run through a hash algorithm, such asHMAC_SHA512, for example, with a pre-determined value for the SHA512key. This would provide a random but reproducible 512 bit buffer (64bytes). From this, the buffer can be partitioned in half into two 32byte buffers using the first 32 bytes as a secret key and the second 32bytes as a chain code. The combination of the secret key and the chaincode is what is referred to as an extended key. From the secret key andthe chain code, child keys can be derived.

As such, from the master key, chain code, and index, child private andpublic keys can be derived in a reproducible fashion. From there, anyprivate key can derive child public and/or private keys based on its ownsecret, chain code, and index, and any public key can only derivecorresponding public keys based on its own secret, chain code, andindex. Also, any private/public key pair that can derive a child keyusing the same index value would be a valid public/private key pair.

Additionally, from a pair of public and private extended keys, anotherlevel (for example, a second level) of 2³¹ keys can be created. In suchan example implementation, 32 bits of data is used as the size for thevalue on which the index is based. One of the bits in the index value isreserved for a special purpose identity when calculating child keys.That said, it should be appreciated by one skilled in the art that oneor more embodiments of the invention need not be limited to 2³¹ keys,and other configurations and/or implementations can be utilized. Fromeach of the second level keys, another level (for example, a thirdlevel) of 2³¹ keys can be derived, and so on.

By way of illustration, the example algorithm detailed below depends onthe index number (i) of the key for derivation (for example, i=0 whenderiving “m/0”) and also on whether the parent key is a public orprivate key. Continuing with the above example, if the index number (i)number is ≧2³¹, then that index number (i) is denoted as a hardened key;otherwise, that index number (i) is denoted as a normal key.

In this example embodiment, deriving a private child key from a privateparent key includes determining whether the key is a hardened key (thatis, whether i≧2³¹) If the key is a hardened key, then I=HMAC_SHA512 (thekey=a parent chain code; data=0x00∥ser256(parent secret key)∥ser32(i)),wherein “serX” represents a serialize integer as X bits, with the mostsignificant byte first. If the key is a normal key, then I=HMAC_SHA512(the key=a parent chain code; data=serp(point(parent secretkey)∥ser32(i)), wherein “serp” represents a serialize key pair usingSEC1's compressed form, and wherein point(p) represents a coordinate keypair from elliptical curve (EC) point multiplication of the secp256k1base point with integer p. As also utilized above and further herein, ∥represents a concatenation operation. Additionally, the first 32 bytesof I are I_(l) and the second 32 bytes are I_(r). The child secret keyis parse256(I_(l))+(parent secret key mod n), and the child chain codeis I_(r). Note also that “n” in “mod n” refers to the modulus parameterfrom the secp256k1 EC.

Also, in such an example embodiment, deriving a public child key from apublic parent key includes determining whether the key is a hardened key(that is, whether i≧2³¹). If the key is a hardened key, a failureindication is returned (as the result is invalid). If the key is anormal key, I=HMAC_SHA512 (the key=a chain code of parent key;data=serp(parent secret key)∥ser32(i)). The first 32 bytes of I areI_(l) and the second 32 bytes are I_(r). The secret childkey=point(parse256(I_(l)))+parent secret key, and the child chain codeis I_(r), wherein+represents an EC group operation.

Further, such an example embodiment can include determining and/ordistinguishing a public child key from a private parent key. By way ofillustration, assume that there is a function N that computes theextended public key from an extended private key (using elliptic keycryptography secp256k1, for example): N(xPriv)→xPub. As such, togenerate a public child key, the result of the above function above“Deriving a private child key from a private parent key=getChildPriv(X)”would be passed to N to generate the child public key, and the childpublic key=N(getChildPriv(Parent Private key)).

In accordance with one or more embodiments of the invention, keys can begenerated in any tree-like structure as required in order to mimic ormirror a given hierarchy of roles or permissions that are required to bemapped for a given implementation. Moreover, in the system that is to beprotected, a hierarchy of permissions is established. This can becarried out, for example, by creating a hierarchy of “roles” in thesystem, wherein each role is given a set of permissions and also grantedone or more additional roles. An example of this is shown in FIG. 2,wherein each noted role (202, 204 and 206) also includes a set ofpermissions corresponding thereto. Once each key pair is generated, thepair can be used to generate request tokens to be sent between twosystems (or devices, users, etc.).

Additionally, because public keys can be generated from a parent publickey, a system wherein the private keys are held does not need to send akey representing a higher level of permission than the other systemrequires. By way of illustration, continuing with the above example, ifusers of System A should not have more than the permissions associatedwith the role of Ops (204), then System B would only need to share theOps-related public key with System A, and at no point could any user onSystem A be able to generate a token with the permissions associatedwith the role of Admin (202). Also, in such an example embodiment,System A can generate the read-only (206) access tokens from the Ops(204) key without having to explicitly receive the read-only key (onlythe child key index). In at least one embodiment of the invention, theindex level is specified for every request such that, for example,System B will know which key to verify against. Additionally, System Awould understand the hierarchy of indexes that mapped to specific rolesso as to generate keys for different levels of permissions below the keythat was shared with a given role.

FIG. 3 is a diagram illustrating an authentication exchange mechanism,according to an example embodiment of the invention. Specifically, FIG.3 depicts a mechanism by which two disparate systems (System A 304 andSystem B 306) can authenticate access between them using one-time logintokens, wherein such tokens can be validated based on deterministichierarchical keys mapping to authorization levels, and only the minimumamount of data needs to be shared between the two systems.

As illustrated in FIG. 3, a user browser 302 corresponding to a userthat is on System A 304 is attempting to authenticate to System B 306.As also depicted in FIG. 3, System B maintains a private key 307 that ismapped to a particular authorization level (m/0/0/0, associated withread-only access in the given example embodiment of the invention).Further, System A maintains a public key 305 that has been generatedbased on the above-noted private key of System B, and associated withthe same particular authorization level (m/0/0/0). In one or moreembodiments of the invention, a third party system can be responsiblefor generating and sharing keys, or System B, in the above example, canbe responsible for generating and sharing keys. In this example, SystemA would not be responsible for generating and sharing keys because itwould not be desirable for System A to have access to the private keys(and thereby gaining access to all levels of authorization on System B).

In the depicted authentication attempt, user browser 302 transmits arequest indication to System A 304. By way of example, this requestindication transmission can include a user (on System A) clicking on alink via user browser 302 that indicates a desire to access a resourceon System B 306 (such as specific data on System B). By way of morespecific example (and in connection with the depicted example of FIG.3), such a request indication can include a transmission to System A 304including, for example, “RequestSystembReadOnlyUrl,” which describes thedesired target at which the user seeks authentication (System B), theauthorization level associated with this specific user (read-only(m/0/0/0)), and the nonce value (time-stamp) associated with thisauthentication request. Accordingly, the user would make a request toSystem A for a resource, while System A would recognize that theresource is on System B and provide the mechanism back to the user forretrieving the resource from System B.

Additionally, based on the information provided by System A 304(generated utilizing System A's public key 305 (Pub-m/0/0/0), the userbrowser 302 transmits an authentication request in combination with thenoted information provided by System A to System B 306. In an exampleembodiment of the invention, the entire transmission to System B wouldnot need to be encrypted, but a portion thereof (such as the “XXX” valuedescribed below, which can be the payload encrypted with the public key)would be encrypted. By way of example (and in connection with thedepicted example of FIG. 3), such a transmission can include “GEThttp://url?token=XXX,” which describes the desired target at which theuser seeks authentication (http://url?), and the login token associatedwith this particular user request (token=XXX), which would include anidentification of the authorization level associated with this specificuser (read-only (m/0/0/0) and the nonce value (time-stamp) associatedwith this authentication request (as generated via System A's public key305).

System B 306 subsequently processes the transmission provided by userbrowser 302 to validate the authentication request. In an exampleembodiment of the invention, System B would decrypt and validate aportion of the request transmission (such as the “XXX” value describedabove, which can be the payload encrypted with the public key).Validating the authentication request includes comparing the includednonce value to the nonce values previously observed by System B todetermine whether the included nonce value is greater than thepreviously received nonce values (for example, that the time-stamprepresents a later point in time than the previously received time-stampvalues). Additionally, validating the authentication request includescomparing the denoted authorization level associated with the requestinguser (associated with public key 305 of System A 304) with theauthorization level associated with the private key 307 of System B 306.If (i) the included nonce value is greater than the previously receivednonce values and (ii) the denoted authorization level associated withthe requesting user matches the authorization level associated withprivate key 307, then System B authenticates the user to access thedesired resource within the limits associated with the notedauthorization level “AuthenticateReadOnlyAccess(XXX)”, as noted in theFIG. 3 example. If one or both of the above-noted aspects of thevalidation process are not successfully completed, then System B candeny the authentication request.

FIG. 4 is a flow diagram illustrating techniques according to anembodiment of the present invention. Step 402 includes generating aplurality of items of key information comprising (i) a first item of keyinformation and (ii) a second item of key information that is derivedfrom the first item of key information. The first item of keyinformation can include a private key, and the second item of keyinformation can include a public key derived from the private key.

Step 404 includes attributing a distinct authorization level, from a setof multiple authorization levels, to the plurality of items of keyinformation to create (i) a modified version of the first item of keyinformation and (ii) a modified version of the second item of keyinformation. In at least one embodiment of the invention, the set ofmultiple authorization levels is arranged in a hierarchy. Additionally,the set of multiple authorization levels can include a set of multiplepre-specified authorization levels within an enterprise, wherein eachrespective one of the multiple pre-specified authorization levelscorresponds to one or more individuals within the enterprise.

Step 406 includes providing the modified version of the first item ofkey information to a first cryptographic device to be used in connectionwith processing an authentication request associated with a secondcryptographic device.

Step 408 includes providing the modified version of the second item ofkey information to the second cryptographic device to be used inconnection with a submission of an authentication request to the firstcryptographic device. Providing the modified version of the second itemof key information to the second cryptographic device can includeproviding the modified version of the second item of key information tothe second cryptographic device to be used in connection with asubmission of an authentication request, to the first cryptographicdevice, pertaining to a user having an authorization level that matchesthe distinct authorization level in the modified version of the seconditem of key information.

At least one embodiment of the invention can also include providing anincremental item of cryptographic information to the secondcryptographic device to be used in connection with submission of anauthentication request to the first cryptographic device. Theincremental item of cryptographic information can include a time-stampand/or a count value.

FIG. 5 is a flow diagram illustrating techniques according to an exampleembodiment of the invention. Step 502 includes processing an indication,generated by a user, to access a protected resource on a cryptographicdevice. Step 504 includes generating, in response to said processing, arequest to authenticate the user to the cryptographic device to accessthe protected resource, wherein said generating comprises encrypting amessage using an item of key information, wherein the item of keyinformation includes a designation of a distinct authorization levelattributed to the user from a set of multiple authorization levels. Theitem of key information can include a public key derived from a privatekey associated with the cryptographic device. The message includes anincremental item of cryptographic information to be used exclusively inconnection with the request to authenticate the user to thecryptographic device to access the protected resource. Step 506 includesinitiating a transmission of the request to the cryptographic device. Inat least one embodiment of the invention, initiating the transmissioncan include providing (via System A, as noted in above examples)information necessary to permit a given user and/or web browser tointeract directly with a particular system (for example, System B).Additionally, by obtaining the encrypted payload with an authorizationlevel, System B can then map that authorization level to a “role” onSystem B and verify the authorization level against the requestedresource on System B.

FIG. 6 is a flow diagram illustrating techniques according to an exampleembodiment of the invention. Step 602 includes processing a request toauthenticate a user to access a protected resource, wherein the requestcomprises an encrypted message including an item of cryptographicinformation. Step 602 includes step 604 and 606.

Step 604 includes decrypting the encrypted message using an item of keyinformation, wherein the item of key information includes a designationof a distinct authorization level, selected from a set of multipleauthorization levels. The item of key information can include a privatekey.

Step 606 includes comparing the item of cryptographic information to oneor more items of cryptographic information observed in connection withone or more previous authentication requests to determine a status ofthe item of cryptographic information in relation to the one or moreitems of cryptographic information observed in connection with the oneor more previous authentication requests.

Step 608 includes resolving the authentication request based on (i) saiddecrypting and (ii) said comparing. Resolving the authentication requestcan include granting access to the protected resource to the user inaccordance with the distinct authorization level if: the encryptedmessage is successfully decrypted using the item of key information, andthe item of cryptographic information satisfies the status determinationof the item of cryptographic information in relation to the one or moreitems of cryptographic information observed in connection with the oneor more previous authentication requests. Additionally, resolving theauthentication request can include denying access to the protectedresource to the user if: the encrypted message is not successfullydecrypted using the item of key information, and/or the item ofcryptographic information does not satisfy the status determination ofthe item of cryptographic information in relation to the one or moreitems of cryptographic information observed in connection with the oneor more previous authentication requests.

FIG. 7 is a diagram illustrating an example embodiment of communicationsystems that may incorporate functionality according to one or moreembodiments of the invention. As described herein, authenticationtechniques of the type associated with one or more embodiments of theinvention may be implemented in a wide variety of differentapplications. By way merely of illustration, one exemplary communicationsystem application that may incorporate such techniques will now bedescribed with reference to FIG. 7.

As depicted in FIG. 7, a communication system 700 comprises a pluralityof mobile devices 702-1 and 702-2 and computers 704-1, 704-2 and 704-3,configured to communicate with one another over a network 706. Any twoor more of the devices 702 and 704 may correspond to cryptographicdevices (such as devices 110-1 and/or 110-N as depicted in FIG. 1)configured to implement at least one embodiment of the invention, asdescribed herein. It is also to be appreciated, however, that thetechniques disclosed herein can be implemented in numerous otherapplications. For example, while FIG. 7 depicts network 706 as awireless network, it is to be appreciated that one or more embodimentsof the invention can be implemented in connection with a wired network.

Further, aspects of the present invention are described herein withreference to flowchart illustrations and/or block diagrams of methods,apparatus, systems and computer program products according toembodiments of the invention. It is to be appreciated that each block ofthe flowchart illustrations and/or block diagrams, and combinations ofblocks in the flowchart illustrations and/or block diagrams, can beimplemented by computer program instructions. These computer programinstructions may be provided to a processor of a special purposecomputer or other specialized programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other specialized programmable dataprocessing apparatus, implement the functions/acts specified in theflowchart and/or block diagram block or blocks.

As further described herein, such computer program instructions may alsobe stored in a computer readable medium that can direct a computer,other programmable cryptographic devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks. Accordingly, as further detailed below, atleast one embodiment of the invention includes an article of manufacturetangibly embodying computer readable instructions which, whenimplemented, cause a cryptographic device to carry out techniquesdescribed herein.

The computer program instructions may also be loaded onto a computer orother devices to cause a series of operational steps to be performed onthe computer, other programmable apparatus or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a component, segment, orportion of code, which comprises at least one executable instruction forimplementing the specified logical function(s). It should be noted thatthe functions noted in the block may occur out of the order noted in thefigures.

Additionally, the techniques detailed herein can also be implemented viaa computer program product that includes computer useable program codestored in a computer readable storage medium in a data processingsystem, wherein the computer useable program code was downloaded over anetwork from a remote data processing system. The computer programproduct can also include, for example, computer useable program codethat is stored in a computer readable storage medium in a server dataprocessing system, wherein the computer useable program code isdownloaded over a network to a remote data processing system for use ina computer readable storage medium with the remote system.

As will be appreciated by one skilled in the art, aspects of the presentinvention may take the form of an entirely hardware embodiment, anentirely software embodiment (including firmware, resident software,micro-code, etc.) or an embodiment combining software and hardwareaspects that may be referred to herein as a “system.”

FIG. 8 is a system diagram of an exemplary cryptographic device (such asdevice 110-1 and/or device 110-N in FIG. 1, for example) on which atleast one embodiment of the invention can be implemented. As depicted inFIG. 8, an example implementation employs, for example, a processor 802,a memory 804, and an input/output interface formed, for example, by adisplay 806 and a keyboard 808. The term “processor” as used herein caninclude one of multiple processing device(s), such as, for example, onethat includes a central processing unit (CPU), a microprocessor, amicrocontroller, an application-specific integrated circuit (ASIC), afield-programmable gate array (FPGA), and/or other forms of processingcircuitry. The term “memory” includes memory associated with a processoror CPU, such as, for example, random access memory (RAM), read onlymemory (ROM), a fixed memory device (for example, a hard drive), aremovable memory device (for example, a diskette), a flash memory, etc.Further, the phrase “input/output interface,” as used herein, includes amechanism for inputting data to the processing unit (for example, agraphical user interface) and a mechanism for providing resultsassociated with the processing unit (for example, a display).

The processor 802, memory 804, and input/output interface such asdisplay 806 and keyboard 808 can be interconnected, for example, via bus810 as part of a data processing unit 812. Suitable interconnections viabus 810, can also be provided to a network interface 814 (such as anetwork card), which can be provided to interface with a computernetwork, and to a media interface 816 (such as a diskette or compactdisc read-only memory (CD-ROM) drive), which can be provided tointerface with media 818.

Accordingly, computer software including instructions or code forcarrying out the techniques detailed herein can be stored in associatedmemory devices (for example, ROM, fixed or removable memory) and, whenready to be utilized, loaded in part or in whole (for example, into RAM)and implemented by a CPU. Such software can include firmware, residentsoftware, microcode, etc.

As noted above, a data processing system suitable for storing and/orexecuting program code includes at least one processor 802 coupleddirectly or indirectly to memory elements 804 through a system bus 810.The memory elements can include local memory employed during actualimplementation of the program code, bulk storage, and cache memorieswhich provide temporary storage of at least some program code in orderto reduce the number of times code must be retrieved from bulk storageduring implementation. Also, input/output (I/O) devices such askeyboards 808, displays 806, and pointing devices, can be coupled to thesystem either directly (such as via bus 810) or through intervening I/Ocontrollers.

Network adapters such as network interface 814 (for example, a modem, acable modem, an Ethernet card, etc.) can also be coupled to the systemto enable the data processing system to become coupled to other dataprocessing systems or remote printers or storage devices throughintervening private or public networks.

As used herein, a “server” includes a physical data processing system(such as system 812 as depicted in FIG. 8) running a server program. Itwill be understood that such a physical server may or may not include adisplay and keyboard.

As noted, at least one embodiment of the invention can take the form ofa computer program product embodied in a computer readable medium havingcomputer readable program code embodied thereon. As will be appreciated,multiple combinations of computer readable media may be utilized. Thecomputer readable medium can include a computer readable signal mediumor a computer readable storage medium. A computer readable storagemedium may be, for example, but not limited to, an electronic, magnetic,optical, electromagnetic, or semiconductor system, apparatus, or device,or any suitable combination of the foregoing. Examples include anelectrical connection having one or more wires, a portable computerdiskette, a hard disk, RAM, ROM, an erasable programmable read-onlymemory (EPROM), flash memory, an optical fiber, a portable CD-ROM, anoptical storage device, a magnetic storage device, and/or any suitablecombination of the foregoing. More generally, a computer readablestorage medium may be any tangible medium that can contain, or store aprogram for use by or in connection with an instruction executionsystem, apparatus, or device.

Additionally, a computer readable signal medium may include a propagateddata signal with computer readable program code embodied therein, forexample, in baseband or as part of a carrier wave. Such a propagatedsignal may take any of a variety of forms such as, for example,electro-magnetic, optical, or a suitable combination thereof. Moregenerally, a computer readable signal medium may be any computerreadable medium that is not a computer readable storage medium and thatcan communicate, propagate, or transport a program for use by or inconnection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium can be transmittedusing an appropriate medium such as, for example, wireless, wireline,optical fiber cable, radio frequency (RF), and/or a suitable combinationof the foregoing. Computer program code for carrying out operations inaccordance with one or more embodiments of the invention can be writtenin any combination of at least one programming language, including anobject oriented programming language, and conventional proceduralprogramming languages. The program code may execute entirely on a user'scomputer, partly on a user's computer, as a stand-alone softwarepackage, partly on a user's computer and partly on a remote computer, orentirely on the remote computer or server. In the latter scenario, theremote computer may be connected to the user's computer through any typeof network, including a local area network (LAN) or a wide area network(WAN), or the connection may be made to an external computer (forexample, through the Internet using an Internet Service Provider).

In light of the above descriptions, it should be understood that thecomponents illustrated herein can be implemented in various forms ofhardware, software, or combinations thereof, for example, applicationspecific integrated circuit(s) (ASICS), functional circuitry, anappropriately programmed digital computer with associated memory, etc.

Terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention.For example, the singular forms “a,” “an” and “the” are intended toinclude the plural forms as well, unless clearly indicated otherwise. Itwill be further understood that the terms “comprises” and/or“comprising,” as used herein, specify the presence of stated features,steps, operations, elements, and/or components, but do not preclude thepresence or addition of another feature, step, operation, element,component, and/or group thereof.

Also, it should again be emphasized that the above-described embodimentsof the invention are presented for purposes of illustration only. Manyvariations and other alternative embodiments may be used. For example,the techniques are applicable to a wide variety of other types ofcommunication systems and cryptographic devices that can benefit fromauthentication techniques. Accordingly, the particular illustrativeconfigurations of system and device elements detailed herein can bevaried in other embodiments. These and numerous other alternativeembodiments within the scope of the appended claims will be readilyapparent to those skilled in the art.

What is claimed is:
 1. A method comprising: generating a plurality ofitems of key information comprising (i) a first item of key informationand (ii) a second item of key information that is derived from the firstitem of key information, wherein said generating comprises (a) creatinga randomly-generated seed attributed to a particular cryptographicdevice, and (b) generating multiple sub-keys derived from therandomly-generated seed, wherein each generated sub-key corresponds to aseparate additional cryptographic device, and wherein both the firstitem of key information and the second item of key informationcorrespond to a distinct one of the generated sub-keys; attributing adistinct authorization level, from a set of multiple authorizationlevels, to the plurality of items of key information to create (i) amodified version of the first item of key information and (ii) amodified version of the second item of key information; providing themodified version of the first item of key information to a firstcryptographic device to be used in connection with processing anauthentication request associated with a second cryptographic device;and providing the modified version of the second item of key informationto the second cryptographic device to be used, in conjunction with adistinct nonce value, in connection with a submission of anauthentication request to the first cryptographic device, wherein theauthentication request identifies (i) the cryptographic device at whichauthentication is sought, (ii) the distinct authorization levelassociated with the modified version of the second item of keyinformation, and (iii) the distinct nonce value, which is associatedspecifically with the authentication request.
 2. The method of claim 1,wherein the first item of key information comprises a private key. 3.The method of claim 2, wherein the second item of key informationcomprises a public key derived from the private key.
 4. The method ofclaim 1, wherein the set of multiple authorization levels is arranged ina hierarchy.
 5. The method of claim 1, wherein the set of multipleauthorization levels comprises a set of multiple pre-specifiedauthorization levels within an enterprise, wherein each respective oneof the multiple pre-specified authorization levels corresponds to one ormore individuals within the enterprise.
 6. The method of claim 1,wherein said providing the modified version of the second item of keyinformation to the second cryptographic device to be used in connectionwith a submission of an authentication request to the firstcryptographic device comprises providing the modified version of thesecond item of key information to the second cryptographic device to beused in connection with a submission of an authentication request, tothe first cryptographic device, pertaining to a user having anauthorization level that matches the distinct authorization level in themodified version of the second item of key information.
 7. The method ofclaim 1, wherein the distinct nonce value comprises the current time. 8.The method of claim 1, wherein the distinct nonce value comprises thecurrent time in milliseconds.
 9. An article of manufacture comprising anon-transitory processor-readable storage medium havingprocessor-readable instructions tangibly embodied thereon which, whenimplemented, cause a processor to carry out steps comprising: generatinga plurality of items of key information comprising (i) a first item ofkey information and (ii) a second item of key information that isderived from the first item of key information, wherein said generatingcomprises (a) creating a randomly-generated seed attributed to aparticular cryptographic device, and (b) generating multiple sub-keysderived from the randomly-generated seed, wherein each generated sub-keycorresponds to a separate additional cryptographic device, and whereinboth the first item of key information and the second item of keyinformation correspond to a distinct one of the generated sub-keys;attributing a distinct authorization level, from a set of multipleauthorization levels, to the plurality of items of key information tocreate (i) a modified version of the first item of key information and(ii) a modified version of the second item of key information; providingthe modified version of the first item of key information to a firstcryptographic device to be used in connection with processing anauthentication request associated with a second cryptographic device;and providing the modified version of the second item of key informationto the second cryptographic device to be used, in conjunction with adistinct nonce value, in connection with a submission of anauthentication request to the first cryptographic device, wherein theauthentication request identifies (i) the cryptographic device at whichauthentication is sought, (ii) the distinct authorization levelassociated with the modified version of the second item of keyinformation, and (iii) the distinct nonce value, which is associatedspecifically with the authentication request.
 10. The article ofmanufacture of claim 9, wherein the distinct nonce value comprises thecurrent time.
 11. The article of manufacture of claim 9, wherein thedistinct nonce value comprises the current time in milliseconds.
 12. Thearticle of manufacture of claim 9, wherein the first item of keyinformation comprises a private key.
 13. A cryptographic devicecomprising: a memory; and a processor coupled to the memory andconfigured to: generate a plurality of items of key informationcomprising (i) a first item of key information and (ii) a second item ofkey information that is derived from the first item of key information,wherein said generating comprises (a) creating a randomly-generated seedattributed to a particular cryptographic device, and (b) generatingmultiple sub-keys derived from the randomly-generated seed, wherein eachgenerated sub-key corresponds to a separate additional cryptographicdevice, and wherein both the first item of key information and thesecond item of key information correspond to a distinct one of thegenerated sub-keys; attribute a distinct authorization level, from a setof multiple authorization levels, to the plurality of items of keyinformation to create (i) a modified version of the first item of keyinformation and (ii) a modified version of the second item of keyinformation; provide the modified version of the first item of keyinformation to a first cryptographic device to be used in connectionwith processing an authentication request associated with a secondcryptographic device; and provide the modified version of the seconditem of key information to the second cryptographic device to be used,in conjunction with a distinct nonce value, in connection with asubmission of an authentication request to the first cryptographicdevice, wherein the authentication request identifies (i) thecryptographic device at which authentication is sought, (ii) thedistinct authorization level associated with the modified version of thesecond item of key information, and (iii) the distinct nonce value,which is associated specifically with the authentication request. 14.The device of claim 13, wherein the set of multiple authorization levelsis arranged in a hierarchy.
 15. The device of claim 13, wherein the setof multiple authorization levels comprises a set of multiplepre-specified authorization levels within an enterprise, wherein eachrespective one of the multiple pre-specified authorization levelscorresponds to one or more individuals within the enterprise.
 16. Thearticle of manufacture of claim 12, wherein the second item of keyinformation comprises a public key derived from the private key.
 17. Thedevice of claim 13, wherein the distinct nonce value comprises thecurrent time.
 18. The device of claim 13, wherein the distinct noncevalue comprises the current time in milliseconds.
 19. The device ofclaim 13, wherein the first item of key information comprises a privatekey.
 20. The device of claim 19, wherein the second item of keyinformation comprises a public key derived from the private key.